Although hip replacement surgery has been common for several decades, and improvements continue to be made, there is still a desire to find ways to allow a patient to retain more of his or her own tissue, especially supporting bone structures. In a conventional total hip replacement, a metallic acetabular cup is affixed inside the patient's acetabulum, and a relatively thick polymeric insert is secured inside the acetabular cup. Because of the thickness of insert, the femoral side of the prosthesis includes a femoral head having a diameter that may be much smaller than the patient's own anatomy. Thus, bone is lost on the acetabular side when the acetabulum is reamed to accommodate the cup, and it is also lost on the femoral side when the neck and head of the patient's femur are resected to accommodate the stem and femoral head of the implant.
In contrast to a conventional total hip replacement, a hip resurfacing may be performed in certain cases, and this may allow a much greater retention of natural tissue. In at least some hip resurfacing surgeries, the head of the patient's femur is sculpted to accommodate a metal cap, and the acetabulum is reamed to accommodate a relatively thin, metal acetabular cup. The result is conservation of more bone than in a conventional total hip replacement, but the femoral side and acetabular side are both metal, which results in metal-to-metal contact and wear over the life of the implant.
Because the acetabular cup is relatively thin, enough bone must be reamed from the patient's acetabulum to ensure that the cup can be inserted with little impact force; otherwise, the thin cup is likely to deform as it is being positioned. Although it may be possible to make the acetabular cup thin enough to accept a polymeric insert, this adds to the likelihood of cup deformation—not only when it is inserted into the acetabulum, but when the insert is seated in the cup. Therefore, a need exists for a system for implanting an acetabular prosthesis that overcomes some or all of the aforementioned shortcomings of existing systems.